Welding with argon helium mixtures

[weld123]

What would be the purpose for welding stainless and nickel alloys with an argon helium mixture for shielding gas. And would it be ok to weld 300 series stainless steels with this mixture?

 

[Rich2001]

Argon is generally used, although there are quality and productivity advantages in using a mixture of either argon and helium or argon and reduced hydrogen. The addition of Helium to Argon produce a hotter arc for a given arc current.

In some application argon alone is used to weld austentic stainless steel while an Argon/Helium mixture is used on the ferritic and martensitic grades.